1. Field of the Invention
The present invention relates to apparatuses and methods using a tool such as a blade to cut a workpiece.
2. Description of the Background Art
Conventionally, silicon substrates, ceramic substrates, printed circuit, boards (hereinafter generally referred to as xe2x80x9csubstratesxe2x80x9d) and silicon ingot, and any other similar workpieces that can readily chip are cut with a rotating blade provided in the form of a disc and containing abrasive grains. In this case is used an apparatus referred to as a dicer, a slicer or the like provided with the blade. These apparatuses are used to cut a substrate, as follows:
A rotating blade can be moved to a substrate fixed on a stage or the stage with the substrate fixed thereon can be moved to the rotating blade to bring the substrate and the rotating blade into contact and thus cut the substrate.
In the above conventional cutting process, however, if the blade is rotated at an increased rate of rotation or its peripheral speed is increased to more efficiently cut the substrate, chips generated in the cutting process are insufficiently removed and the blade thus receives an increased working resistance from the substrate. Therefore the substrate is cut inefficiently and friction also increases the blade""s surface temperature and thus reduces the blade""s life.
Furthermore, the increased working resistance may result in the cut workpiece having burrs, since the workpiece may still have a portion thereof remaining that should have completely been removed. In particular, if a silicon substrate is cut to provide a semiconductor chip for a chip size package (CSP) and the chip has burrs, the chip may fail to be mounted on a PCB printed circuit board) snugly and by extension may introduce defective connection. Such burrs thus impair the CSP in reliability.
The present invention contemplates cutting apparatuses capable of providing enhanced working efficiency and reducing burrs and also increasing the life of a blade, and methods thereof.
The above object is achieved by the present invention in one aspect providing a cutting apparatus including: a fixture device or means for fixing a workpiece thereto; cutting means for cutting the workpiece, including a blade rotating around a shaft""s center and thus contacting the workpiece to cut the workpiece; a drive mechanism or means for moving the blade and the workpiece at a predetermined relative rate of movement to allow the blade and the workpiece to contact each other; and an oscillation mechanism or means for oscillating the shaft""s center at a predetermined rate of oscillation in a plane identical to a plane in which the blade cuts the workpiece, wherein the rate of oscillation is greater than the relative rate of movement.
Thus the center of the shaft of the rotating blade can provide a rapid, small oscillation at the predetermined rate of oscillation greater than the relative rate of movement, while the blade can move and thus cut the workpiece fixed to the fixture device. Thus, while it travels a distance, the blade repetitively contacts the workpiece and is disengaged therefrom more frequently. Therefore, the workpiece being cut exerts a decreased working resistance because the workpiece contacts the blade for shorter periods of time and is also out of contact with the blade for certain periods of time.
Furthermore in the present apparatus in the first aspect the oscillation mechanism may revolve the shaft""s center around a center of a predetermined revolution at a predetermined rate of rotation with a predetermined radius of rotation in a predetermined direction of rotation to oscillate the shaft""s center.
Furthermore in the present apparatus in the first aspect the blade and the shaft""s center may rotate in the same direction.
Thus the rate of rotation of the shaft""s center can accelerate the blade""s peripheral speed relative to the workpiece to cut the workpiece more efficiently.
Furthermore in the present apparatus in the first aspect the blade and the shaft""s center may rotate in opposite directions.
Furthermore in the present apparatus in the first aspect the oscillation mechanism may reciprocate the shaft""s center, as predetermined, to oscillate the shaft""s center.
Furthermore in the present apparatus in the first aspect the oscillation mechanism may move the shaft""s center in a predetermined ellipse to oscillate the shaft""s center.
Furthermore in the present apparatus in the first aspect the oscillation mechanism may utilize a piezoelectric effect of a piezoelectric element to oscillate the shaft""s center.
Furthermore in the present apparatus in the first aspect the oscillation mechanism may composite a reciprocating oscillation having one direction and a reciprocating oscillation having another direction different from the one direction together to oscillate the shaft""s center.
Furthermore the present invention in a second aspect provides a cutting apparatus including: a fixture device or means for fixing a workpiece thereto; cutting means for cutting the workpiece including a blade rotating around a shaft""s center and thus contacting the workpiece to cut the workpiece; a drive mechanism or means for moving the blade and the workpiece at a predetermined relative rate of movement to allow the blade and the workpiece to contact each other; and an oscillation mechanism or means for oscillating the fixture device at a predetermined rate of oscillation in a plane identical to a plane in which the blade cuts the workpiece, wherein the rate of oscillation is greater than the relative rate of movement.
Thus the fixture device can provide a rapid, small oscillation at the predetermined rate of oscillation greater than the relative rate of movement, while the blade can move and thus cut the workpiece fixed to the fixture device. Thus, while it travels a distance, the blade repetitively contacts the workpiece and is disengaged therefrom more frequently. Therefore, the workpiece being cut exerts a decreased working resistance because the workpiece contacts the blade for shorter periods of time and is also out of contact with the blade for certain periods of time.
Furthermore in the present apparatus in the second aspect the oscillation mechanism may revolve the fixture device around a center of a predetermined revolution at a predetermined rate of rotation with a radius of rotation in a direction of rotation to oscillate the fixture device.
Furthermore, in the present apparatus in the second aspect the blade and the fixture device may rotate in the same direction.
Thus the rate of rotation of the fixture device can accelerate the blade""s peripheral speed relative to the workpiece to cut the workpiece more efficiently.
Furthermore in the present apparatus in the second aspect the blade and the fixture device may rotate in opposite directions.
Furthermore in the present apparatus in the second aspect the oscillation mechanism may reciprocate the fixture device, as predetermined, to oscillate the fixture device.
Furthermore in the present apparatus in the second aspect the oscillation mechanism may move the fixture device in a predetermined ellipse to oscillate the fixture device.
Furthermore in the present apparatus in the second aspect the oscillation mechanism may utilize a piezoelectric effect of a piezoelectric element to oscillate the fixture device.
Furthermore in the present apparatus in the second aspect the oscillation mechanism may composite a reciprocating oscillation having one direction and a reciprocating oscillation having another direction different from the one direction together to oscillate the fixture device.
To achieve the above object the present invention in a first aspect provides a method using a blade rotating around a shaft""s center to cut a workpiece fixed to fixture device, including the steps of: oscillating the shaft""s center at a predetermined rate of oscillation in a plane identical to a plane in which the blade cuts the workpiece; moving the blade and the workpiece at a predetermined relative rate of movement; and bringing the blade and the workpiece into contact with each other to cut the workpiece, wherein in the step of oscillating, the rate of oscillation is greater than the relative rate of movement.
Thus the center of the shaft of the rotating blade can provide a rapid, small oscillation at the predetermined rate of oscillation greater than the relative rate of movement, while the blade can move and thus cut the workpiece fixed to the fixture device. Thus, while it travels a distance, the blade repetitively contacts the workpiece and is disengaged therefrom more frequently. Therefore, the workpiece being cut exerts a reduced working resistance because the workpiece contacts the blade for shorter periods of time and is also out of contact with the blade for certain periods of time.
Furthermore in the present method in the first aspect the step of oscillating may include revolving the shaft""s center around a center of a predetermined revolution at a predetermined rate of rotation with a predetermined radius of rotation in a predetermined direction of rotation to oscillate the shaft""s center.
Furthermore the present invention in a second aspect provides a method using a blade rotating around a shaft""s center to cut a workpiece fixed to fixture device, including the steps of: oscillating the fixture device at a predetermined rate of oscillation in a plane identical to a plane in which the blade cuts the workpiece; moving the blade and the workpiece at a predetermined relative rate of movement; and bringing the blade and the workpiece into contact with each other to cut the workpiece, wherein in the step of oscillating, the rate of oscillation is greater than the relative rate of movement.
Thus the fixture device can provide a rapid, small oscillation at the predetermined rate of oscillation greater than the relative rate of movement, while the blade can move and thus cut the workpiece fixed to the fixture device. Thus, while it travels a distance, the blade repetitively contacts the workpiece and is disengaged therefrom more frequently. Therefore, the workpiece being cut exerts a reduced working resistance because the workpiece contacts the blade for shorter periods of time and is also out of contact with the blade for certain periods of time.
Furthermore in the present method in the second aspect the step of oscillating may include revolving the fixture device around a center of a predetermined revolution at a predetermined rate of rotation with a predetermined radius of rotation in a predetermined direction of rotation to oscillate the fixture device.
Furthermore in the present method in the first or second aspect in the step of oscillating the direction in which the blade rotates around the shaft""s center may be identical to the direction in which the shaft""s center or the fixture device rotates.
With the rate of rotation the blade and the workpiece in a vicinity of a location allowing them to contact each other can move in opposite directions constantly opposite each other. This can increase the blade""s peripheral speed relative to the workpiece to cut the workpiece more efficiently.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.